A common state of the art loudspeaker has a cone supporting a coil that can act as an electromagnet, and a permanent magnet. The cone, which may be made by paper, is typically movable in relation to the permanent magnet. When an electric signal is delivered to the coil, the coil acts as an electromagnet to generate a magnetic field acting on the permanent magnet so as to cause the cone to move in relation to the permanent magnet. In some sound reproduction systems, multiple loudspeakers may be used, each reproducing a part of the audible frequency range. Miniature loudspeakers are found in devices such as radio and TV receivers, and many forms of music players. Larger loudspeaker systems are used for music reproduction e.g. in private homes, in cinemas and at concert arenas.